-- Add CASCADE to all foreign keys referencing candidate to allow candidate deletion
ALTER TABLE app.candidate_document
DROP CONSTRAINT candidate_document_candidate_id_fkey,
ADD CONSTRAINT candidate_document_candidate_id_fkey
  FOREIGN KEY (candidate_id)
  REFERENCES app.candidate(candidate_id)
  ON DELETE CASCADE;

ALTER TABLE app.candidate_education
DROP CONSTRAINT candidate_education_candidate_id_fkey,
ADD CONSTRAINT candidate_education_candidate_id_fkey
  FOREIGN KEY (candidate_id)
  REFERENCES app.candidate(candidate_id)
  ON DELETE CASCADE;

ALTER TABLE app.candidate_transcript
DROP CONSTRAINT candidate_transcript_candidate_id_fkey,
ADD CONSTRAINT candidate_transcript_candidate_id_fkey
  FOREIGN KEY (candidate_id)
  REFERENCES app.candidate(candidate_id)
  ON DELETE CASCADE;

ALTER TABLE app.candidate_license
DROP CONSTRAINT candidate_license_candidate_id_fkey,
ADD CONSTRAINT candidate_license_candidate_id_fkey
  FOREIGN KEY (candidate_id)
  REFERENCES app.candidate(candidate_id)
  ON DELETE CASCADE;

ALTER TABLE app.candidate_language
DROP CONSTRAINT candidate_language_candidate_id_fkey,
ADD CONSTRAINT candidate_language_candidate_id_fkey
  FOREIGN KEY (candidate_id)
  REFERENCES app.candidate(candidate_id)
  ON DELETE CASCADE;

ALTER TABLE app.candidate_experience
DROP CONSTRAINT candidate_experience_candidate_id_fkey,
ADD CONSTRAINT candidate_experience_candidate_id_fkey
  FOREIGN KEY (candidate_id)
  REFERENCES app.candidate(candidate_id)
  ON DELETE CASCADE;

-- Delete duplicate emails, keeping only the first created occurrence
DELETE FROM app.candidate
WHERE candidate_id NOT IN (
  SELECT candidate_id
  FROM (
    SELECT candidate_id,
           ROW_NUMBER() OVER (PARTITION BY email ORDER BY created_at ASC) as rn
    FROM app.candidate
    WHERE email IS NOT NULL
  ) sub
  WHERE rn = 1
);

-- Add email verification token to user table for double opt-in
ALTER TABLE app.user ADD COLUMN email_verification_token VARCHAR;

-- Remove magic_link_expiry since JWT handles expiry internally
ALTER TABLE app.user_auth DROP COLUMN magic_link_expiry;

-- Add unique constraint to candidate email to prevent duplicate registrations
ALTER TABLE app.candidate ADD CONSTRAINT candidate_email_unique UNIQUE (email);

-- Add field to track when incomplete process reminder was sent
ALTER TABLE app.candidate ADD COLUMN incomplete_reminder_sent_at TIMESTAMP;